Clinical inclusion criteria:
1. Age ranging between 18 and 80 years.
2. Ischemic events (TIA or ischemic stroke) related to the occluded artery, occurring despite aggressive medical management, with the last event occurring within between 14 and 90 days prior to enrollment.
3. The modified Rankin Scale (mRS) score 0-2 at the time of enrollment.
4. At least one risk factor for atherosclerosis.
5. All enrolled patients refused bypass surgery.
6. Signatured informed consent form.
Imaging inclusion criteria:
1. Occlusion of intracranial ICA, M1 segment of MCA, intracranial VA (with contralateral VA hypoplasia or occlusion), or BA, as confirmed by CT angiography (CTA) or digital subtraction angiography (DSA), and the length of the cclusion segment was≤15mm.
2. A decrease of \>30% in cerebral blood flow in the territory distal to the target region, as assessed by CT perfusion (CTP); or inadequate collateral compensation indicated by digital subtraction angiography (DSA), defined as an ASITN/SIR collateral grade of 0-2; or evidence of hemodynamic ischemic lesions on CT or MRI.
3. Alberta Stroke Program Early CT Score (ASPECTS) ≥ 6 for anterior circulation occlusion, or posterior circulation ASPECTS (pc-ASPECTS) ≥ 6 and pons-midbrain index (PMI) \< 3 for posterior circulation occlusion, as demonstrated by CT or MRI.
4. Technical feasibility of endovascular recanalization (ER) in the qualifying artery evaluated by two experienced interventional neuroradiologists.
Exclusion Criteria:
1. Severe stenosis (70%-99%) or occlusion of other arteries, or tandem stenosis (70%-99%) that is proximal to the qualifying artery.
2. Intracranial hemorrhagic diseases such as definite Intracranial tumors, any intracranial vascular malformations, hemorrhagic transformation of infarction, spontaneous intracranial hemorrhage (cerebral parenchymal, subarachnoid, subdural, or epidural) within 30 days.
3. Non atherosclerotic intracranial artery disease: arterial dissection, moyamoya disease or moyamoya syndrome demonstrated by imaging examination, or a definite medical history of autoimmune vasculitis.
4. Evidence of cardioembolic embolism such as atrial fibrillation, prosthetic valve(s), infective endocarditis, mitral stenosis, atrial myxoma, intracardiac clot or vegetation, left ventricular aneurysms, etc.
5. Known unstable angina or myocardial infarction within the last 6 months.
6. Intolerance or allergic reaction to any treatment-related medication, including aspirin, clopidogrel, heparin, and local or general anesthetics.
7. History of life-threatening allergy to contrast dye.
8. Severe liver impairment (AST or ALT \> 3 times normal, cirrhosis), serum creatinine \> 3.0 mg/dl.
9. Past history of EC-IC bypass surgery or EVT.
10. Major surgery (including open femoral, aortic, or carotid surgery) within previous 30 days or planned in the next 90 days after enrollment.
11. Late-stage malignant tumors, cachexia, or other serious diseases and an expected life expectancy of less than 1 year.
12. Pregnant, perinatal stage or lactating women.
13. Any other condition (in the opinion of the site investigator) that inappropriate to participate this study.
